White lines along gum line?

I have a small white line at the edge of my gums, close to my teeth. When I first discovered it I thought it was plaque but realized it was part of my gums. I'm setting a dentist appointment tomorrow, because I have a feeling I may have other problems. My gums around one of my teeth is red, like blood is on the inside and its really sore when I brush and it bleeds, while the rest of my mouth doesn't. The rest of my mouth was bleeding at one point, but stop and just today my gums at the bottom were bleeding a little. What do you think all these symptoms could be?